Detector stand



Wee. 18 1923. lAWfiZfi I R. J. HEITZMAN DETECTOR STAND Filed June 29. 1922 i i i i Patented Dec. 18, 1923.

ROBERT J. HEITZMAN, F UNION HILL, NEW JERSEY.

DETECTOR STAND.

Application filed June 29, 1922. Serial No. 571,598.

To all 1c]: om it may concewr:

Be it known that 1, ROBERT J. HEITZMAN, a citizen of the United States, residing at Union llill, in the county of Hudson and State of New Jersey, have invented certain new and useful Improvements in Detector Stands; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to makeand use the same.

T he invention relates to a novel form of detector for wireless telegraph and telephone circuits of. the crystal type, and has for its object to provide a relatively simple, strong and durable device that is capable of very delicate adjustment, but which nevertheless is not subject to displacement or derangement of its parts or the relative adjustment thereof, due to shocks and jars, or the passage of relatively heavy currents or sparks,

' so that, when the apparatus has been properly adjusted, any accidental change in such adjustment is precluded.

The invention is illustrated in the accompanying drawings, in which, Fig. 1 is a side elevation of the device;

Fig. 2 is a plan view thereof;

Fig. 3 is an end elevation;

'Fig. t is a section on line 4-4 of Fig. 1.

Referring to the drawings, 1 indicates the base or support of. the instrument, which is made of suitable insulating material, and which may be secured by any appropriate means to the cabinet Orother receptacle in which the radio apparatus is contained. Mounted on the upper surface of the support 1 is av bracket 2, preferably formed of a metal stamping having a rectangulai'ly disposed foot-piece 3' provided with upturned ends and an elongated slot or perforation 4, through which passes a set-screw 6' cxtending from the bottom of the support 1 through a perforation in the latter, and having a hollow cap-nut T engaging the threaded end thereof. enclosing a helical tension spring 8, the parts being so constructed and arranged as to admit of a wide range of adjustment of the bracket 2 in the plane of the upper surface of the support 1, the bracket nevertheless being held firmly in its adjusted position on the base 1 by the tension imposed on the spring 8 by the cap-nut 7.

. The upper portion of the bracket is provided with lateral extensions and 6, on the former of which is mounted a pivot pin 11 carrying a lever 10, preferably stamped out of sheet metal, having a flange 12 extending at right angles to its rear end, and provided at its forward end with an eye or 100 13 stamped from the body of the metal. etween the pivot 11 and the flange 12, said lever is provided with an integral lug 14 bent at right angles to the body thereof to receive the upper looped end of a helical tension spring 15, the lower looped end of which is hooked over an integral projection 9 extending at right angles to the body of the bracket 2.

Mounted in the arm 6 of the bracket 2 is a pintle 21 having a knurled head 22, between which and the face of the bracket is interposed a tension spring 23. Secured to the outer end of the pintle 21 is a circular cam 20, so disposed that its axis is eccentrio and its peripheral edge is in engagement with the flange 12 on the lever 10, these parts being held in constant engagement by the tension spring 15.

Secured in the eye or loop 13 on the forward end of the bracket is a contact needle or cat whisker 16, which is additionally secured to the lever by loopin the upper end thereof over the topof the lever. The needle or cat whisker is preferably made of relatively fine spring wire bent in the form of a double loop or figure 8 below its attachment to the lever, and having its lower end extending downwardly in a line substantially normal to the longitudinal axis of the lever 10.

The needle 16 is adapted to co-operate with a crystal of the character usually employed in instruments of this type, the crystal mass, which may consist either of a block of appropriate mineral, or a small mass of the mineral enclosed in a suitable casing open at the top, is adjustably secured to the base 1 by means of a Z-shaped spring clip 18, which is attached to the top of the base and is provided in its upper horizontal with an opening 19 overlying the crystal. Secured to the base are suitable binding posts and 31 to which the circuit leads are attached.

Inasmuch as the effectiveness of a detector of this character depends in a large measure on the proper regulation of the conthe crystal, it will be seen that the apparatus as described affords .means, not only for effecting an extreme delicacy of adjustment of the contact, but also presents a co-ordinw;

' tion of parts which will prevent any derangenient of the adjustmentby accidental means, such, for example, as shocks or blows imparted to the apparatus, or the passage of a heavy spark. The double loop 17 in the needle renders the latter sufliciently resilient to respond toundue pressure, without, however, causing the needle to be displaced on the surface of the crystal by ordinary shocks or jars, while the action of the circular cam 20 on the outer end of the lever'lO, acting in opposition to the tension spring 15, ad mits of a very accurate degree of contact pressure between the end of the lever and the crystal being obtained and maintained, as the cam is held in its adjusted position against accidental displacement by the ac tion of the tension spring 23 on the pintle 21, which holds the pintle and cam vagainst movement. In order to obtain a proper contact between the end of the needle 16 and the crystal, it is frequently necessary to move or ad usteither the needle or the crystalor both. The adjustment of the crystal may be readily effected by shifting the position of the same under the spring clip 18,

and the relative position of the needle on the surface'of the crystal may be readily effected by shifting the bracket backward and forward or angularly on the top of the base; this latter adjustment being permitted by reason of the elongated slot 4% in the foot 3, which co-operates with the set-screw 6, the tension spring 8, while exercising enough pressure on the foot 3 to hold the bracket in its adjusted osition, nevertheless permitting the bracliet to ,be readily adjusted or moved in the direction of the longitudinal axis of the slot, or angularly thereto.

If it is found that the bracket cannot be readily shifted on the base, it is only necesvsary to turn the cap-nut backward a little to relieve the tension of the spring, and after the proper adjustment has been effected, the cap-nut is again set up to cause the spring to retain the bracket firmly in position, and

What I claim is: l. A detector stand for radi'dapparatus comprisinga base, a bracket normal to the base, a lever of the first class pivoted to said bracket, a cam journalled on the bracket engaging the rear end of said lever, a spring connected with the lever to hold the latter in engagement with the cam, a contact needle of spring wire attached to the forward part of the lever, and a crystal holding spring clip secured to the base below the needle, I

2. A detector stand for; radio apparatus comprising a base, a bracket having a body normal to the base and afoot engaging the base, spring tension means forv adjustably securing the foot to the base, a lever of the first class pivoted to said-bracket, a cam .journalled on the bracket engaging the rear with the cam, a contact needle of spring wire attached to the forward part of the 'gitudinal slot therein engaging to the base,

a screw in the base engaging said slot, a nut on said screw, a spring surrounding the screw and interposed between the nut and foot, a lever of the first class pivoted to said 'end of said lever,"a spring connected with v the lever to hold the latter in engagement bracket, a cam journalled on the bracket engaging therear end of said lever, a spring connected with the lever to hold the latter in engagement wlththe cam, a contact needle of spring wire attached to the forward part of the lever, and a crystal holding spring clip secured to the base below the needle.

. 4. A detector stand for radio apparatus comprising a base, a bracket normal thereto and mounted for adjustment in the plane of the base, a lever of the first class pivoted to said bracket, a cam journalled on said bracket engagingthe rear end of said lever, a spring holding the cam and. lever in engagement, a contact needle of spring wire attached tothe forward'end of the lever," said. needle having a double loop of figure 8 form intermediate its ends, and a perforated sprin clip for adjustably clamping a crystal to the base below the needle.

5. A detector stand for radio a paratus comprising a base, a bracket norma thereto and mounted for adjustment in the plane of the base. a lever of the first class pivoted to said bracket, a rotary cam'engagmg the rear end of said lever, a bolt journalled in,

the bracket having said cam fixed to its outer 1 end, a compression spring between the head without liability of accidental displacementa bf' the bolt and the bracket, a spring holding the cam and lever in engagement, a

.contact needle of spring wire attached to the'forward end of'the lever, said needle.

In testimony whereof I afiix my signature. I

ROBERT J. HEITZMAN. 

